In spite of modern improvements in hygiene and infection prevention, livestock health has become an increasingly important public health issue. This has been due in part to the fact that infections caused by viruses and fungi have increased as a result of travel and global interconnections.
Pathogens such as bacteria, fungi, viruses, and bacterial spores are responsible for a plethora of human and animal ills, as well as contamination of food and biological and environmental samples. The first step in microbial infections of animals is generally attachment or colonization of skin or mucus membranes, followed by subsequent invasion and dissemination of the infectious microbe. The portals of entry of pathogenic bacteria are predominantly the skin and mucus membranes.
Virtually every intensive livestock producer accepts that effective disease prevention is key for maintaining a healthy enterprise. Over the years the improvement in and availability of vaccines has greatly assisted in the prevention of a large number of diseases. However, even a well vaccinated livestock can succumb under severe challenge. Moreover, since vaccines are not available for all the diseases to be prevented, producers have accepted that a well planned and monitored bio-security program, coupled with an effective disinfection and vaccination program, is essential for maintaining the health of their stock.
Avian influenza is an infectious disease of birds caused by type A strains of the influenza virus. The disease, which was first identified in Italy more than 100 years ago, occurs worldwide. All birds are thought to be susceptible to infection with avian influenza, though some species are more resistant to infection than others. Domestic poultry, including chickens and turkeys are particularly susceptible to epidemics of rapidly fatal influenza.
Fifteen subtypes of influenza virus are known to infect birds, thus providing an extensive reservoir of influenza viruses potentially circulating in bird populations. To date, all outbreaks of the highly pathogenic form have been caused by influenza A viruses of subtypes H5 and H7. Recent research has shown that that viruses of low pathogenicity can, after circulating for sometimes short periods in a poultry population, mutate into highly pathogenic viruses.
The quarantining of infected farms and destruction of infected or potentially exposed flocks are standard control measures aimed at preventing spread to other farms and eventual establishment of the virus in a country's poultry population. Apart from being highly contagious, avian influenza viruses are readily transmitted from farm to farm by mechanical means, such as by contaminated equipment, vehicles, feed, cages, or clothing. Stringent sanitary measures on farms can, however, confer some degree of protection.
A great many of the current antimicrobial compositions, including sanitizers and disinfectants, contain antimicrobial agents which are not naturally occurring. Typical antimicrobial agents used in sanitizers and disinfectants include chemical disinfectants such as phenolic compounds, quaternary ammonium compounds, formaldehyde and halogen containing compounds. Such materials are not of natural origin (i.e. not found in nature) and are prepared through chemical processing and synthesis. A great many of these “synthetic” disinfectants cause undesirable effects on both the environment and on human health. The concept of formulating disinfectants, essentially involving the selection of a simple chemical disinfectant and enhancing its activity by adding other chemicals, evolved in the seventies.
The enhancement of the activity of a simple chemical disinfectant or combination of simple disinfectants to increase the spectrum of activity frequently involves the addition of additional chemical agents. Such additional chemical agents will generally have an effect on the pH and surface activity of the formulated product once in solution. It is well established that a number of simple disinfectants demonstrate their optimum activity at a specific pH (i.e. acidity or alkalinity). The ability of the disinfectant solution to make complete and even contact with the surface to be treated is also of great importance. This can generally be achieved by the addition of a surfactant or detergent to the formulation.
Disinfectants play a vital role in any biosecurity system, both in the process of terminal disinfection and in the ongoing hygiene maintenance. Apart from relatively minor changes and improvements in formulations, there has been little innovation in livestock disinfectant and large-surface disinfectant development for some fifteen to twenty years.
While some natural plant oils have been known since antiquity to have curative properties, the topical and oral benefits of natural plant oils have more recently been attributed to antimicrobial properties. A great many of the natural essential oils are derived from cajeput, cedarwood, citronella, clove, cypress, fir-needle, eucalyptus, garlic, lavender, lemon, lemongrass, marjoram, niaouli, onion, orange, oregano, patchouli, peppermint, rosemary, rosewood, tea tree, y-lang and vetivert. Of these natural essential oils, oregano oil, comprising a complex mixture of antimicrobial compounds, has been used as a reference for the comparison of the bactericidal action of other substances owing to its near ideal antibacterial properties. Oregano oil has been demonstrated as exerting a high degree of anti-fungal, anti-parasitic, antiviral and antibacterial action. The phenolic flavenoids carvacol and thymol are two potent natural antiseptic agents encountered primarily in oregano oil.
Attempts have been made to formulate disinfectant solutions based upon essential oils. However, because of their hydrophobic nature, essential oils are not readily miscible in water. As a result, essential oils are often difficult to prepare in a form that will allow them to be readily incorporated into an aqueous solution.
U.S. Pat. No. 5,403,587 issued to McCue et al. on Apr. 4, 1995 discloses an antimicrobial composition that uses both a solvent and a surfactant to facilitate the formation of a homogeneous aqueous mixture of an essential oil. However, this composition is not suitable for disinfecting large surfaces such as commonly encountered in agricultural settings where the disinfectant solution is commonly prepared from a concentrate using the on-site water source.
The present invention refers to a number of documents, the content of which is herein incorporated by reference in their entirety.